核壳结构半导体纳米晶体CdS/ZnS的制备及其光学性质

通过反胶束法成功制备了CdS及CdS/ZnS核壳结构量子点，采用紫外-可见吸收光谱(UV-Vis)、透射电子显微镜(TEM)、能量色散型X射线能谱(EDX)以及荧光光谱(PL)等对其结构和性能进行了研究。与CdS量子点相比，CdS/ZnS量子点的粒径明显变大，本文估算了粒子的粒径，TEM图像很好的印证了估算的结果；结合EDX的测试结果可以推断CdS/ZnS量子点的结构是ZnS包裹在CdS表面的核壳结构；CdS/ZnS量子点的荧光强度与CdS量子点相比有了明显的提高，原因主要是壳层的ZnS消除了CdS量子点表面上存在的无辐射复合中心。

Synthesis of CdS/ZnS core-shell quantum dots in reverse micelle system and its optical property research

CdS and CdS/ZnS quantum dots were synthesized by the microemulsion method in sulfosuccinic acid bis(2-ethylhexyl)ester sodium salt(AOT) surfactant reverse micelles containing water.The products were characterized by UV-Vis spectrometer, transmission electronmicroscopy (TEM), energy dispersive X-ray spectroscope (EDX)and photoluminescence(PL) spectroscope.The diameter of CdS/ZnS nanoparticle was obvious larger than that of CdS nanoparticle.The diameter of the nanoparticle was estimated, which was confirmed by the images of TEM.The existence of core-shell structure was established by the result of energy dispersive X-ray analysis. PL studies of the samples showed that the luminescence from CdS was enhanced by the ZnS shell.A possible reason was that the ZnS shell reduced the number of defects on the surface of CdS quantum dots, which were assumed to act as centers for radiation-free recombination.